1. Field of the Invention
The present invention relates to a search server and a method for providing search results or necessary information efficiently to users who browse information via a network.
2. Description of the Prior Art
There are a lot of search engines exhibited on the Internet for searching web pages described in HTML (Hypertext Markup Language). Most of the search engines utilize a technique including registering process and searching process. In the registering process, a crawler and a program repeat a process of tracing links described in a web page one by one, so as to have cyclic access to web pages on the Internet and to collect web pages. The collected web pages and URLs are registered in a database. In the searching process, a search condition (mainly keywords) that a user entered is checked against the database so that web pages matching the search condition are found and provided to the user as search results.
In addition, there is a search engine that ranks plural web pages obtained as the search results and display them in descending order of the rank, so that the user can find the target web page easily. As the ranking method (condition), several methods are used such as a method of checking occurrence frequency of the keywords that the user entered, a method of utilizing an HTML structure (e.g., a title or a header portion is assigned with high weight) or a method of checking the number of links from other web pages in accordance with the link structure.
The user may check the ranked search results and may click a URL portion in the display, so that a web page of the search results is displayed on the browser. Most web pages that are currently provided are based on character data, and a lot of words and phrases are contained in a web page. Therefore, the user can find a target web page by the search with designating plural keywords.
Not only the search engines for web pages, image search engines for searching images on the Internet for example are also exhibited on the Internet. Such an image search engine utilizes the HTML structure and a method that utilizes text neighboring an image or a caption of an image. Therefore, the method for searching images is not so different from the method for searching web pages based on character data. The user can check the search results and browse the web page where the desired image is exhibited by click operation using a mouse in the same way as the search based on the character data. Thumbnail images are used as the search results so that a user can find a target image easily.
In addition, along with improvement of performances of a computer and a network, the number of web pages that use a lot of data (especially image data)-and utilize a virtual three-dimensional space for expressing three-dimensional contents has been increasing. Japanese unexamined patent publication No. 2000-172248 discloses one of such techniques, in which a link is utilized for displaying plural contents simultaneously in a virtual three-dimensional space. Contents of the link destination are overlaid on the link origin, and the link destination contents are displayed in smaller size than the link origin contents. Zoom operation enables the link destination to be enlarged in the display, so that plural link destinations are displayed one by one sequentially.
However, most web sites do not contain all information in one web page, but the information is divided into plural web pages that are linked to each other. As a result, the information displayed in one web page is limited, and it may be difficult to understand the contents of the web page only by a glance of the web page that was found to contain the keyword. In this case, information of the link origin or other web pages is necessary. Especially in the case of a web page that contains images mainly or utilizes a virtual three-dimensional space, character information contained in one web page is so little that it is difficult to find a target by the method of searching keywords contained in the web page.
Furthermore, in a normal HTML browser, the abrupt change of the screen display caused by the click operation at the link-embedded portion may puzzle the user. As a solution to that problem, there is a method of changing the plural contents of display continuously in a virtual three-dimensional space. However, it is difficult to use the conventional search technique effectively for such a method.